It doesn't work either, a result similar with what I get with "-forceidx".

The sad thing is, if I use divx encoded AVIs, all is good: the join work perfectly (either with cat and forceidx or with one step mencoder) but it is suboptimal: transcode from theora to divx > join the avis > transcode back to theora, two transcoding options and a huge quality loss.

I see two losing options: drop Ogg Theora and do everything as DivX AVI or drop the screencast at all. Frustrating. And don't get me started about the lack of a nice GUI for all this process... (PiTiVi)

but still no luck: in Totem and Mplayer it exit (cleanly) after the end of the first part and in VLC it open two video windows and play both clips at the same time until the end of clip1 and then exit cleanly.